Heat transfer augmentation by using twisted tapes as inserts for tube side flow of liquids with convection

Abstract

This concept deals with the effect of twisted tape inserts as Passive Heat transfer augmentation device. Effect twisted tape (TT), on heat transfer and friction factor for heating of water for Reynolds number range 250030000, was studied experimentally in a double pipe counter flow heat exchanger. One tape of different twist ratio (yw=3.69, yw=4.39, yw=5.25) for Twisted tape (TT), were used. Based on constant flow rate, the heat transfer coefficient was found to be 1.18-3.66, times the smooth tube values for Twisted tape (TT), respectively. The nusselt number values were found to be 3.23-5.96 times the smooth tube values for Twisted tape (TT), respectively. Based on constant pumping power, the heat transfer coefficient values were found to be 0.88-1.62, times the smooth tube values for Twisted tape (TT), respectively. Based on the increase in Heat transfer coefficient, Performance evaluation criteria R1 & R3, it was concluded that twisted tape performs much better than the smooth tube.